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Newly
found Enzymes may play early role in Cancer
Newswise — Researchers have discovered two
enzymes that, when combined, could be
involved in the earliest stages of cancer.
Manipulating these enzymes genetically might
lead to targeted therapies aimed at slowing
or preventing the onset of tumors.
“We could conceivably reactivate a
completely normal gene in a tumor cell – a
gene that could prevent the growth of a
tumor if reactivated,” says David Jones,
Ph.D., professor of oncological sciences at
the University of Utah and senior director
of early translational research at the
university’s Huntsman Cancer Institute (HCI).
“We believe this could be one of the
earliest processes to go wrong in cancer,”
he adds.
"By manipulating these enzymes, we could
possibly prevent or slow the onset of
tumors.”
The enzymes appear to control an “on–and-off
switch” for critical genes that could
trigger cancer or numerous other diseases
and birth defects.
The research is published in the December 26
issue of Cell.
Using zebrafish that share similar genetics
to humans, the HCI scientists identified a
previously unknown enzyme process that
controls the levels of DNA methylation on
genes.
“Methylation is a cellular process that is
required for healthy cell growth and
development, but it can go awry in cancer
and diseased cells,” says Brad Cairns,
Ph.D., HCI investigator and professor of
oncological sciences at the University of
Utah.
“You
can think of DNA methylation as an
on-and-off switch. Methylation silences or
‘shuts off’ genes that need to be turned off
or are not functioning as they should,
whereas the reverse process called
demethylation ‘turns on’ healthy genes and
genes needed at critical times in
development,” he says.
In cancer, this methylation process goes
haywire, leading to tumor growth. Genes that
should be “turned on” are not and vice
versa.
The significance of this research is the
discovery of two enzymes involved in DNA
demethylation. Defects in DNA methylation
balance are strongly associated with the
early development of cancer, other diseases
and birth defects, and the scientists say
their study is the first clear evidence that
this enzyme system plays a critical role in
maintaining this balance. They also believe
it’s a process that can be reversed.
Further research will reveal if DNA
methylation levels can be manipulated
genetically.
If so, it could lead to drugs to reactivate
particular genes and suppress tumor growth.
Remarkably, this system also helps protect
the genome from mutations.
“We discovered a pair of enzymes that can
remove methylated DNA, but if these enzymes
work improperly, they will instead enhance
the rate of mutations in methylated DNA and
cause cancer progression,” says Jones.
“The question now is, when they work
improperly, can we find ways to shut them
off and prevent these mutations?”
The enzymes leading to DNA demethylation
involve the coupling of a 5-meC deaminase
enzyme, a G:T glycosylase enzyme and Gadd45,
which is not an enzyme.
The mission of Huntsman Cancer Institute (HCI)
at the University of Utah is to understand
cancer from its beginnings, to use that
knowledge in the creation and improvement of
cancer treatments, to relieve the suffering
of cancer patients, and to provide education
about cancer risk, prevention, and care.
HCI is a National Cancer
Institute-designated cancer center, which
means that it meets the highest national
standards for cancer care and research and
receives support for its scientific
endeavors.
HCI is also a member of the National
Comprehensive Cancer Network (NCCN) a
not-for-profit alliance of the world’s
leading cancer centers, which is dedicated
to improving the quality and effectiveness
of care provided to patients with cancer.
For more information about HCI, please visit
www.huntsmancancer.org .
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